Review Article
Abstract
The benefits and risks of nutritional therapies in the prevention and management of infectious diseases in the developed world are reviewed. There is strong evidence that early enteral feeding of patients prevents infections in a variety of traumatic and surgical illnesses. There is, however, little support for similar early feeding in medical illnesses. Parenteral nutrition increases the risk of infection when compared to enteral feeding or delayed nutrition. The use of gastric feedings appears to be as safe and effective as small bowel feedings. Dietary supplementation with glutamine appears to lower the risk of post-surgical infections and the ingestion of cranberry products has value in preventing urinary tract infections in women.
Background
One of the earliest responses to infection is cytokine-mediated anorexia. Interleukins 1, 6, 8 as well as tumor necrosis factor and interferon alpha are released by host defense mechanisms. These cytokines reduce nutrient intake through effects on the central nervous system [1]. They also cause the sequestration of critical nutrients such as iron, copper and zinc in order to allow the host to gain an advantage over invading organisms [2]. Is it a benefit to bypass the action of the body's host defense mechanisms by feeding patients who do not or cannot ingest their normal diet?
The developed world is rife with calories and nutrients. Is there a benefit from nutritional supplements in preventing infections in societies where the availability of nutrients is not limited?
Physicians are often asked about the role of various nutritional interventions in preventing or treating infectious diseases. What is known about the value of these interventions?
This review will not deal with nutritional interventions in populations which often suffer dietary deficiencies. As such, it will include only studies done in economically developed nations. Finally, it will review the use of cranberry products and yogurt as these are available in any grocery store, but not the myriad of botanical products sold for their medicinal value.
In order to clarify what is known about the risks and benefits of nutrition in the developed world, I have reviewed the English language publications available on MEDLINE (1966–2006) and in the Cochrane Library which deal with nutrition and infection. All articles including the words "nutrition", "vitamin(s)", "cranberry" or "yogurt" and the words "infection" or "infectious" in their abstracts were reviewed. Articles were included if they were structured to compare differing nutritional interventions.
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Professor of Medicine, College of Medicine, University of Toledo, 3120 Glendale Avenue, Toledo, OH 43614, USA
Nutrition Journal 2006, 5:21 doi:10.1186/1475-2891-5-21
The electronic version of this article is the complete one and can be found online at: http://www.nutritionj.com/content/5/1/21
© 2006 Donabedian; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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